Random is random. Some people have terrible luck with both, great luck with both, one or the other. I got 3 fetches out of my Khans of Tarkir fatpack, and ***** all out of my Battle For Zendikar one and all the Oath of the Gate Watch ones I opened for the land packs. Meanwhile in boxes I did a lot better, but statistically that makes sense because I have several more chances to open something good.
(Also known as Xenphire)
I agree on the random factor you mention.